rc.d scripts and rc.conf variable defaults

[Ian Lepore]

We have about 165 scripts in etc/rc.d.  22 of them handle their own
default values for configuration variables using ${var:=default} or
${var:-default}.  Presumably all the others rely on defaults/rc.conf
providing the default values.

Is there a standard, written or not, covering this?

rc.conf(5) says that defaults/rc.conf is the thing that includes your
/etc/rc.conf, and that would certainly guarantee that the system-
provided defaults are in place, but the current implementation doesn't
actually work that way.  rc.subr is currently forgiving of a missing
defaults file.

I'd prefer that the system rc.d scripts relied on defaults/rc.conf
alone and individual rc.d scripts not be cluttered up with :- syntax.
 While rc.conf(5) strongly implies the file is required, it doesn't
exactly say so.  Should it?

-- Ian